提问人：Curious Jorge - user9788072 提问时间：8/10/2022 更新时间：8/10/2022 访问量：318
如何从代码的 JS 部分运行 R 代码？
How to run R code from inside a JS section of code?
问：
我现在已经有一些 R 经验，但对 JS 知之甚少。下面的可重现代码使用 JS 运行包 jsTreeR，以便用户可以自定义构建层次结构树。我想用这一段 R 代码替换带有注释标记的可重现代码中的 JS 行（大约在代码的一半，在函数内部），以生成从 A 到 ZZ 的大写字母的顺序列表：// HELP!!script <-c(LETTERS, sapply(LETTERS, function(x) paste0(x, LETTERS)))
有什么想法怎么做吗？
该代码允许用户将元素从层次结构树的“菜单”部分拖放到下面的“拖动到此处以构建树”部分，结构反映在右侧的数据帧中。
我确实在网上找到了一些相关问题，但它们已经过时了。也许从那时起情况有所改善，例如一个从 R 转换为 JS 的漂亮包。谁知道呢。
可重现的代码：
library(jsTreeR)
library(shiny)
nodes <- list(
list(
text = "Menu",
state = list(opened = TRUE),
children = list(
list(text = "Bog",type = "moveable"),
list(text = "Hog",type = "moveable")
)
),
list(
text = "Drag here to build tree",
type = "target",
state = list(opened = TRUE)
)
)
checkCallback <- JS("
function(operation, node, parent, position, more) {
if(operation === 'copy_node') {
var n = parent.children.length;
if(position !== n || parent.id === '#' || node.parent !== 'j1_1' || parent.type !== 'target') {
return false;
}
}
if(operation === 'delete_node') {
if (node.type == 'item'){
text = node.text;
Shiny.setInputValue('deletion', text, {priority: 'event'});
} else if (node.type == 'subitem'){
text = parent.text;
Shiny.setInputValue('deletionsub', text, {priority: 'event'});
}
}
return true;
}"
)
customMenu <- JS("
function customMenu(node) {
var tree = $('#mytree').jstree(true);
var items = {
'delete' : {
'label' : 'Delete',
'action' : function (obj) {
parent = tree.get_node(node.parent);
nodetype = node.type;
orgid = node.orgid;
tree.delete_node(node);
},
'icon' : 'fa fa-trash'
},
};
if (node.type == 'item') {return {'delete':items.delete}}
else return {}
}
"
)
dnd <- list(
always_copy = TRUE,
inside_pos = "last",
is_draggable = JS(
"function(node) {",
" return node[0].type === 'moveable';",
"}"
)
)
mytree <- jstree(
nodes,
dragAndDrop = TRUE, dnd = dnd,
checkCallback = checkCallback,
contextMenu = list(items = customMenu),
types = list(moveable = list(), target = list())
)
script <- '
var LETTERS = ["A", "B", "C", "D", "E", "F"]; // HELP!!
var Visited = {};
function getSuffix(orgid){
if (Object.keys(Visited).indexOf(orgid) === -1){Visited[orgid] = 0;}
else{Visited[orgid]++;}
return LETTERS[Visited[orgid]];
}
$(document).ready(function(){
$("#mytree").on("copy_node.jstree", function(e, data){
var orgid = data.original.id;
var node = data.node;
var id = node.id;
var basename= node.text;
var text = basename + " " + getSuffix(orgid);
Shiny.setInputValue("choice", text, {priority: "event"});
var instance = data.new_instance;
instance.rename_node(node, text);
node.type = "item"
node.basename = basename;
node.orgid = orgid;
var tree = $("#mytree").jstree(true);
});
});
'
ui <- fluidPage(
tags$div(class = "header", checked = NA,tags$p(tags$script(HTML(script)))),
fluidRow(
column(width = 4,jstreeOutput("mytree")),
column(width = 8,verbatimTextOutput("choices"))
)
)
server <- function(input, output, session){
output[["mytree"]] <- renderJstree(mytree)
Choices <- reactiveVal(data.frame(choice = character(0)))
observeEvent(input[["choice"]], {Choices(rbind(Choices(), data.frame(choice = input[["choice"]])))} )
observeEvent(input[["deletion"]], {
item = input[["deletion"]]
matched = which(Choices()$choice == item)
if (length(matched)>0) Choices(Choices()[-matched, , drop = FALSE])
})
output[["choices"]] <- renderPrint({Choices()})
}
shinyApp(ui=ui, server=server)
答：
2赞
r2evans
8/10/2022
#1
从你的一部分开始（只是为了演示，你使用完整的东西）：script
script <- '
var Visited = {};
function getSuffix(orgid){
if (Object.keys(Visited).indexOf(orgid) === -1){Visited[orgid] = 0;}
else{Visited[orgid]++;}
return LETTERS[Visited[orgid]];
}'
我们可以这样做：
script <- paste("var LETTERS =", jsonlite::toJSON(c(LETTERS, sapply(LETTERS, function(x) paste0(x, LETTERS)))), ";", script)
这给了我们：
cat(script, "\n")
var LETTERS = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","AA","AB","AC","AD","AE","AF","AG","AH","AI","AJ","AK","AL","AM","AN","AO","AP","AQ","AR","AS","AT","AU","AV","AW","AX","AY","AZ","BA","BB","BC","BD","BE","BF","BG","BH","BI","BJ","BK","BL","BM","BN","BO","BP","BQ","BR","BS","BT","BU","BV","BW","BX","BY","BZ","CA","CB","CC","CD","CE","CF","CG","CH","CI","CJ","CK","CL","CM","CN","CO","CP","CQ","CR","CS","CT","CU","CV","CW","CX","CY","CZ","DA","DB","DC","DD","DE","DF","DG","DH","DI","DJ","DK","DL","DM","DN","DO","DP","DQ","DR","DS","DT","DU","DV","DW","DX","DY","DZ","EA","EB","EC","ED","EE","EF","EG","EH","EI","EJ","EK","EL","EM","EN","EO","EP","EQ","ER","ES","ET","EU","EV","EW","EX","EY","EZ","FA","FB","FC","FD","FE","FF","FG","FH","FI","FJ","FK","FL","FM","FN","FO","FP","FQ","FR","FS","FT","FU","FV","FW","FX","FY","FZ","GA","GB","GC","GD","GE","GF","GG","GH","GI","GJ","GK","GL","GM","GN","GO","GP","GQ","GR","GS","GT","GU","GV","GW","GX","GY","GZ","HA","HB","HC","HD","HE","HF","HG","HH","HI","HJ","HK","HL","HM","HN","HO","HP","HQ","HR","HS","HT","HU","HV","HW","HX","HY","HZ","IA","IB","IC","ID","IE","IF","IG","IH","II","IJ","IK","IL","IM","IN","IO","IP","IQ","IR","IS","IT","IU","IV","IW","IX","IY","IZ","JA","JB","JC","JD","JE","JF","JG","JH","JI","JJ","JK","JL","JM","JN","JO","JP","JQ","JR","JS","JT","JU","JV","JW","JX","JY","JZ","KA","KB","KC","KD","KE","KF","KG","KH","KI","KJ","KK","KL","KM","KN","KO","KP","KQ","KR","KS","KT","KU","KV","KW","KX","KY","KZ","LA","LB","LC","LD","LE","LF","LG","LH","LI","LJ","LK","LL","LM","LN","LO","LP","LQ","LR","LS","LT","LU","LV","LW","LX","LY","LZ","MA","MB","MC","MD","ME","MF","MG","MH","MI","MJ","MK","ML","MM","MN","MO","MP","MQ","MR","MS","MT","MU","MV","MW","MX","MY","MZ","NA","NB","NC","ND","NE","NF","NG","NH","NI","NJ","NK","NL","NM","NN","NO","NP","NQ","NR","NS","NT","NU","NV","NW","NX","NY","NZ","OA","OB","OC","OD","OE","OF","OG","OH","OI","OJ","OK","OL","OM","ON","OO","OP","OQ","OR","OS","OT","OU","OV","OW","OX","OY","OZ","PA","PB","PC","PD","PE","PF","PG","PH","PI","PJ","PK","PL","PM","PN","PO","PP","PQ","PR","PS","PT","PU","PV","PW","PX","PY","PZ","QA","QB","QC","QD","QE","QF","QG","QH","QI","QJ","QK","QL","QM","QN","QO","QP","QQ","QR","QS","QT","QU","QV","QW","QX","QY","QZ","RA","RB","RC","RD","RE","RF","RG","RH","RI","RJ","RK","RL","RM","RN","RO","RP","RQ","RR","RS","RT","RU","RV","RW","RX","RY","RZ","SA","SB","SC","SD","SE","SF","SG","SH","SI","SJ","SK","SL","SM","SN","SO","SP","SQ","SR","SS","ST","SU","SV","SW","SX","SY","SZ","TA","TB","TC","TD","TE","TF","TG","TH","TI","TJ","TK","TL","TM","TN","TO","TP","TQ","TR","TS","TT","TU","TV","TW","TX","TY","TZ","UA","UB","UC","UD","UE","UF","UG","UH","UI","UJ","UK","UL","UM","UN","UO","UP","UQ","UR","US","UT","UU","UV","UW","UX","UY","UZ","VA","VB","VC","VD","VE","VF","VG","VH","VI","VJ","VK","VL","VM","VN","VO","VP","VQ","VR","VS","VT","VU","VV","VW","VX","VY","VZ","WA","WB","WC","WD","WE","WF","WG","WH","WI","WJ","WK","WL","WM","WN","WO","WP","WQ","WR","WS","WT","WU","WV","WW","WX","WY","WZ","XA","XB","XC","XD","XE","XF","XG","XH","XI","XJ","XK","XL","XM","XN","XO","XP","XQ","XR","XS","XT","XU","XV","XW","XX","XY","XZ","YA","YB","YC","YD","YE","YF","YG","YH","YI","YJ","YK","YL","YM","YN","YO","YP","YQ","YR","YS","YT","YU","YV","YW","YX","YY","YZ","ZA","ZB","ZC","ZD","ZE","ZF","ZG","ZH","ZI","ZJ","ZK","ZL","ZM","ZN","ZO","ZP","ZQ","ZR","ZS","ZT","ZU","ZV","ZW","ZX","ZY","ZZ"] ;
var Visited = {};
function getSuffix(orgid){
if (Object.keys(Visited).indexOf(orgid) === -1){Visited[orgid] = 0;}
else{Visited[orgid]++;}
return LETTERS[Visited[orgid]];
}
评论
0赞
Curious Jorge - user9788072
8/10/2022
嗨 r2evans，所以看起来 jsonlite 提供从 R 到 JS 的翻译？在你上面的例子中，我不确定如何实现。我是否插入行脚本 <- 粘贴（“var LETTERS...）到我的代码的脚本部分，我有 var LETTERS = [“A”,...]？我试过了，但没有用。另外，你有 cat（script， “\n”），那是什么？
2赞
r2evans
8/10/2022
不完全正确，尽管接近：正在从 R 对象转换为 JSON，这是 javascript 对象表示法，通常用作轻量级（准通用）数据交换格式。您无法在 javascript 中执行 R 代码，我正在做的是将 R 代码的结果注入 javascript 代码字符串中。我使用use纯粹是为了展示它的样子。对于您的代码，请按原样定义，但不定义，然后运行我的单行。jsonlite::toJSONcat(script,"\n")scriptLETTERSscript <- paste("var LETTERS =", ...)
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